shouting as a stimulu
Among the inhibitory inputs to the alpha motor neurones are those arising from the golgi tendon organs, a sensory device located within a tendon which protects the muscle from possible injury by causing the muscle to relax or limit the number of muscle fibres recruited during an activity. This reflex relaxation process is protective in nature and is to prevent muscle rupture.
During maximal force production, athletes sometimes yell or scream as they produce a force in an attempt to produce more force, run faster, lift heavier. However, does this actually produce more force? Will yelling override the golgi tendon organ? It is the purpose of this experiment to examine the effect of shouting on handgrip strength.
Equipment (handgrip dynamometers)
Students measure and record their maximal handgrip strength for both dominant and non-dominant hand both quietly and shouting
- To allow appropriate recovery between trials and so that everyone is involved we need to get into groups of four/five.
- The instructor will identify who is group 1, 2 etc.
- Within your group identify who is A, B, C & D.
Stage 1: Do not make any noise or encouragement
- The order of assessment should be as follows: –
- Student A dominant hand.
- Student B dominant hand.
- Student C Non-dominant hand.
- Student D Non-dominant hand.
- Student A Non-dominant hand.
- Student B Non-dominant hand.
- Student C dominant hand.
- Student D dominant hand.
- On completion repeat the trial in the same order, but this time shout the word Strength while you squeeze the dynamometer.
- Record your result in the table below
Successful sporting achievement is highly associated with a sound knowledge of the underlying scientific principles of physiology. The force an athlete can produce is determined by different physiological factors such as muscle mass, neural activation and muscle fibre types and will therefore vary amongst individuals. Understanding how force production is also influenced by the type of muscle action is fundamental to our understanding of human physiology. The purpose of this experiment is to explore the resultant forces/torques produced during three different muscle actions. NB. Torque is a representative value of force in a rotational context.
Your instructor will lead half the laboratory group through the experiment.
With the participant seated, eccentric and concentric assessment of the maximal force of the right quadriceps at 30 degrees per second will be recorded, followed by an isometric muscle action at 55 degrees angle of extension.